Ultrastructural appearance of a perineuronal Phagocytic Microglial cell in the chronic demyelinating plaque of RSA59 infected mouse spinal cord. Electron micrograph (a) shows Microglial cells surrounding the demyelinated axon in a demyelinating plaque region of RSA59 infected mouse spinal cord. Microglia has a heterochromatic nucleus with multiple vacuoles. High-magnification images (b) and (c) demonstrates the presence of Microglia surrounding the unraveling myelin sheath in an axon. The Microglia cell membrane is in intimate contact with the outer portion of the myelin sheath as the Microglia is stripping away (phagocytizing) the myelin sheath and engulfs the myelin sheath. Multiple vacuoles with myelin fragments are seen within the cytoplasm of the activated microglia (phagocytotic in nature)—Figure 5 adopted from [12].